Lots of things really:

1. Aetheris: geometry CAD kernel, https://github.com/yuechen-li-dev/Aetheris/.

Full code CAD capability with big coverage already and some functionalities that even OpenCascade/Parasolid/ACIS doesn't have, full sheet metal module, programmable part assembly, analytical fillets/chamfers, mathematical knots, auto-route for piping, built-in finite element analysis, etc. Had Astra make an improved version of the V8 demo that was going around on LinkedIn, so it can do general hard surface modeling pretty well too, turn all the Astra demo prowess into reusable capabilities/templates. The DSL is human writable too, so give it a try if you want. https://aetheris-editable-v8.yuechenli.workers.dev/

2. Concept language: https://github.com/yuechen-li-dev/Concept

I've said before that Carbon isn't a real programming language, never mind a successor to C++, so I decided to put my money where my mouth is. The idea of it is to be more TypeScript to C++'s JavaScript and to generalize C++20 concepts from template constraints to what C++26 is doing with contracts, and bring the equivalent of Rust's borrow checker to be opt-in by default instead of opt-out, fast compile time, in a syntax that C++ users are already familiar with (`const auto` instead of `let` for example) as well as templates and comptime. Language is done-ish, not self hosted yet, still compiles to C11, kernel and allocator libraries are finished, currently working on the scheduler right now.

3. Copeland TS, https://github.com/yuechen-li-dev/copeland

TypeScript for .NET without all the weirdness of Javascript, with full Nuget and NPM inter-op, Rust style exhaustive `match`, templates, etc. It's actually weird how much cleaned up TypeScript ended up looking like cleaned up C++. Compiles to JS, C#, WASM via Blazor WebAssembly, and SPIR-V via HLSL/DXC, and runs on V8 for JS and RyuJIT/NativeAOT for C#. The conclusion is that RyuJIT ended up being ~2x faster than V8 JS in hot loops but the cold startup time is higher, so replacing JS for UI really isn't worth it. Comes with full UI layout system, Vulkan renderer, and game/app runtime, but those are still pretty rough.